The Great Brain Experiment is all about science. With your help we can better understand the mind and brain.
Below are the scientific publications from the app, announcing what we've found so far. All are free to download.

Basic reward processing is intact in people with major depression

Rutledge et al., August 2017. JAMA Psychiatry

Reward prediction errors represent the difference between what we get and what we expected to get, and we use these signals (linked to dopamine) to learn about the world around us. Major depression has been associated with a reduced impact of reward prediction errors on neural and emotional measurements in tasks where subjects have to learn associations between cues and rewards. However, we found that, in tasks that do not require significant learning, reward prediction errors have similar impacts on the brain and on mood in depressed and non-depressed subjects. Our results were shown using brain scanning in the lab and in 1,833 players of ‘The Great Brain Experiment’. These results suggest that the dopamine system that produces reward prediction errors is probably functioning normally in depression and that the reward-related symptoms of depression have a different cause.

In this study we report results from more than 30,000 players of the card game. We investigated biases which influence how people make decisions.
The results identified three biases related to 'Pavlovian Approach' - the tendancy to choose items associated with rewards. Such behaviors could explain decisions that seem irrational: while advantageous to our evolutionary ancestors, primitive behaviors may bias how we sample information about the world, even when that information is irrelevant, leading to suboptimal choices amongst people today.

In this study we report the latest findings from the reward and happiness game. We found
that older players were less likely to choose risky gambles to win more points. However, they were no different
to younger players when it came to choosing risky gambles to avoid losing points. It is widely believed
that older people don’t take risks, but the study shows exactly what kind of risks older people avoid.
- See more at:

Hearing a particular sound in a noisy environment is a challenging task. This paper presents
results from the 'How well can I hear' game, which involved listening to a pair of sounds and deciding which
one contained a 'target' sound. Using data from more than 5000 players of the app, we found that players
are able to hear out target sounds in background noise, paralleling results from highly controlled experiments
performed in the laboratory. However, the ability to filter out sounds, both in terms of accuracy and speed,
declines as we get older.
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In this paper we report results from the Fruit Tap game, which measures impulsivity and self-control.
We found that the speed with which one can 'apply the brakes' and stop an action - in other words, self-control - gets worse
as we age, but more so for men than women. Whereas men are better at self-control at young ages, around age 50 women overtake them.
We may speculate that this is related to known faster decline of brain areas including prefrontal cortex in men.
We have also made the data from this paper available online
so other researchers can investigate the results from these 29,000+ players.

Age-related changes in working memory and the ability to ignore distraction

McNab et al., May 2015. Proceedings of the National Academy of Sciences USA

A key feature of The Great Brain Experiment is that it enables scientists to compare people of different age groups, giving a window into how the mind and brain change as we age.
As we get older we can hold less information in our minds. Using data from 29,000 players of the app, we found that the picture isn't just one of cognitive decline.
Instead, it appears that the way we hold items in mind – and deal with any distractions as we're trying to remember things – changes as we get older.

Rutledge et al., August 2014. Proceedings of the National Academy of Sciences USA

This is the first result of the reward and happiness game. The game involves making a series of decisions, which sometimes lead to wins
and sometimes to losses. Players are asked to report their momentary happiness as they go through the game. The results show that a simple mathematical
model can predict players' momentary happiness from past rewards and expectations, and functional MRI showed which brain areas might explain how much happiness changes during the game.

McNab and Dolan, July 2014. Journal of Experimental Psychology: Human Perception and Performance

This is first set of findings from the memory game. It shows that when we try to remember things, there are two separate kinds of distraction
which may cause us difficulty - distraction while we take on new information, and distraction when we're holding things in our mind's eye (working memory).
This proof of concept paper shows these distinct kinds of distraction are found both in the highly controlled setting of the laboratory and via 3,247 players of the app.

This is the proof of concept paper looking at the first four games in the app. It shows that mobile apps can be used to conduct robust
scientific experiments which reproduce known laboratory results. This means we can address questions that weren't practical before.
For instance, we can see how people of different ages and backgrounds compare on everyday tasks such as memory and decision making. Furthermore,
the people playing the games are from all round the world, giving us a much better representative sample of the population than could be gained
in a traditional lab experiment. This is an exciting new way to do science, and this first comprehensive paper set the tone for subsequent
discoveries from The Great Brain Experiment.